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dhcpcd/client.c
Roy Marples 24c57f1305 Set the rfds correctly so we can get a reply after re-sending a request. 
Set the seconds elasped and maximum message size correctly in DHCP messages.
Now compiles on Linux 2.4 kernels.
2006-12-01 12:50:53 +00:00

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/*
* dhcpcd - DHCP client daemon -
* Copyright (C) 2006 Roy Marples <uberlord@gentoo.org>
*
* dhcpcd is an RFC2131 compliant DHCP client daemon.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <sys/select.h>
#include <arpa/inet.h>
#ifdef __linux__
#include <netinet/ether.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "arp.h"
#include "common.h"
#include "configure.h"
#include "dhcp.h"
#include "dhcpcd.h"
#include "interface.h"
#include "logger.h"
#include "signals.h"
#include "socket.h"
/* We need this for our maximum timeout as FreeBSD's select cannot handle
any higher than this. Is there a better way of working this out? */
#define SELECT_MAX 100000000
/* This is out mini timeout.
Basically we resend the last request every TIMEOUT_MINI seconds. */
#define TIMEOUT_MINI 3
#define STATE_INIT 0
#define STATE_REQUESTING 1
#define STATE_BOUND 2
#define STATE_RENEWING 3
#define STATE_REBINDING 4
#define STATE_REBOOT 5
#define STATE_RENEW_REQUESTED 6
#define STATE_RELEASED 7
#define SOCKET_CLOSED 0
#define SOCKET_OPEN 1
#define SOCKET_MODE(_mode) \
{ \
if (iface->fd >= 0) close (iface->fd); \
iface->fd = -1; \
if (_mode == SOCKET_OPEN) \
if (open_socket (iface, false) < 0) { retval = -1; goto eexit; } \
mode = _mode; \
}
#define SEND_MESSAGE(_type) \
{ \
last_type = _type; \
last_send = uptime (); \
send_message (iface, dhcp, xid, _type, options); \
}
static int daemonise (char *pidfile)
{
if (daemon (0, 0) < 0)
{
logger (LOG_ERR, "unable to daemonise: %s", strerror (errno));
return -1;
}
make_pid (pidfile);
return 0;
}
unsigned long random_xid (void)
{
static int initialized;
if (! initialized)
{
int fd;
unsigned long seed;
fd = open ("/dev/urandom", 0);
if (fd < 0 || read (fd, &seed, sizeof(seed)) < 0)
{
logger (LOG_WARNING, "Could not load seed from /dev/urandom: %m");
seed = time (0);
}
if (fd >= 0)
close(fd);
srand(seed);
initialized++;
}
return rand();
}
/* This state machine is based on the one from udhcpc
written by Russ Dill */
int dhcp_run (options_t *options)
{
interface_t *iface;
int mode = SOCKET_CLOSED;
int state = STATE_INIT;
struct timeval tv;
int xid = 0;
long timeout = 0;
fd_set rset;
int maxfd;
int retval;
dhcpmessage_t message;
dhcp_t *dhcp;
int type = DHCP_DISCOVER;
int last_type = DHCP_DISCOVER;
bool daemonised = false;
unsigned long start = 0;
unsigned long last_send = 0;
int sig;
unsigned char *buffer = NULL;
int buffer_len = 0;
int buffer_pos = 0;
if (! options || (iface = (read_interface (options->interface,
options->metric))) == NULL)
return -1;
/* Remove all existing addresses.
After all, we ARE a DHCP client whose job it is to configure the
interface. We only do this on start, so persistent addresses can be added
afterwards by the user if needed. */
flush_addresses (iface->name);
dhcp = xmalloc (sizeof (dhcp_t));
memset (dhcp, 0, sizeof (dhcp_t));
strcpy (dhcp->classid, options->classid);
if (options->clientid[0])
strcpy (dhcp->clientid, options->clientid);
else
sprintf (dhcp->clientid, "%s", ether_ntoa (&iface->ethernet_address));
if (options->requestaddress.s_addr != 0)
dhcp->address.s_addr = options->requestaddress.s_addr;
signal_setup ();
while (1)
{
if (timeout > 0 || (options->timeout == 0 &&
(state != STATE_INIT || xid)))
{
if (options->timeout == 0 || dhcp->leasetime == -1)
{
logger (LOG_DEBUG, "waiting on select for infinity");
maxfd = signal_fd_set (&rset, iface->fd);
retval = select (maxfd + 1, &rset, NULL, NULL, NULL);
}
else
{
/* Resend our message if we're getting loads of packets
that aren't for us. This mainly happens on Linux as it
doesn't have a nice BPF filter. */
if (iface->fd > -1 && uptime () - last_send >= TIMEOUT_MINI)
SEND_MESSAGE (last_type);
logger (LOG_DEBUG, "waiting on select for %d seconds",
timeout);
/* If we're waiting for a reply, then we re-send the last
DHCP request periodically in-case of a bad line */
retval = 0;
while (timeout > 0 && retval == 0)
{
if (iface->fd == -1)
tv.tv_sec = SELECT_MAX;
else
tv.tv_sec = TIMEOUT_MINI;
if (timeout < tv.tv_sec)
tv.tv_sec = timeout;
tv.tv_usec = 0;
start = uptime ();
maxfd = signal_fd_set (&rset, iface->fd);
retval = select (maxfd + 1, &rset, NULL, NULL, &tv);
timeout -= uptime () - start;
if (retval == 0 && iface->fd != -1 && timeout > 0)
SEND_MESSAGE (last_type);
}
}
}
else
retval = 0;
/* We should always handle our signals first */
if (retval > 0 && (sig = signal_read (&rset)))
{
switch (sig)
{
case SIGINT:
logger (LOG_INFO, "receieved SIGINT, stopping");
retval = 0;
goto eexit;
case SIGTERM:
logger (LOG_INFO, "receieved SIGTERM, stopping");
retval = 0;
goto eexit;
case SIGALRM:
logger (LOG_INFO, "receieved SIGALRM, renewing lease");
switch (state)
{
case STATE_BOUND:
case STATE_RENEWING:
case STATE_REBINDING:
state = STATE_RENEW_REQUESTED;
break;
case STATE_RENEW_REQUESTED:
case STATE_REQUESTING:
case STATE_RELEASED:
state = STATE_INIT;
break;
}
timeout = 0;
xid = 0;
break;
case SIGHUP:
if (state == STATE_BOUND || state == STATE_RENEWING
|| state == STATE_REBINDING)
{
logger (LOG_INFO, "received SIGHUP, releasing lease");
SOCKET_MODE (SOCKET_OPEN);
xid = random_xid ();
if ((open_socket (iface, false)) >= 0)
SEND_MESSAGE (DHCP_RELEASE);
SOCKET_MODE (SOCKET_CLOSED);
unlink (iface->infofile);
}
else
logger (LOG_ERR,
"receieved SIGUP, but no we have lease to release");
retval = 0;
goto eexit;
default:
logger (LOG_ERR,
"received signal %d, but don't know what to do with it",
sig);
}
}
else if (retval == 0) /* timed out */
{
switch (state)
{
case STATE_INIT:
if (iface->previous_address.s_addr != 0)
{
logger (LOG_ERR, "lost lease");
xid = 0;
SOCKET_MODE (SOCKET_CLOSED);
if (! options->persistent)
{
free_dhcp (dhcp);
memset (dhcp, 0, sizeof (dhcp_t));
configure (options, iface, dhcp);
}
if (! daemonised)
{
retval = -1;
goto eexit;
}
break;
}
if (xid == 0)
xid = random_xid ();
else
{
logger (LOG_ERR, "timed out");
if (! daemonised)
{
retval = -1;
goto eexit;
}
}
SOCKET_MODE (SOCKET_OPEN);
timeout = options->timeout;
iface->start_uptime = uptime ();
if (dhcp->address.s_addr == 0)
{
logger (LOG_INFO, "broadcasting for a lease");
SEND_MESSAGE (DHCP_DISCOVER);
}
else
{
logger (LOG_INFO, "broadcasting for a lease of %s",
inet_ntoa (dhcp->address));
SEND_MESSAGE (DHCP_REQUEST);
state = STATE_REQUESTING;
}
break;
case STATE_BOUND:
case STATE_RENEW_REQUESTED:
state = STATE_RENEWING;
xid = random_xid ();
case STATE_RENEWING:
iface->start_uptime = uptime ();
logger (LOG_INFO, "renewing lease of %s", inet_ntoa
(dhcp->address));
SOCKET_MODE (SOCKET_OPEN);
SEND_MESSAGE (DHCP_REQUEST);
timeout = dhcp->rebindtime - dhcp->renewaltime;
state = STATE_REBINDING;
break;
case STATE_REBINDING:
logger (LOG_ERR, "lost lease, attemping to rebind");
SOCKET_MODE (SOCKET_OPEN);
SEND_MESSAGE (DHCP_DISCOVER);
timeout = dhcp->leasetime - dhcp->rebindtime;
state = STATE_INIT;
break;
case STATE_REQUESTING:
logger (LOG_ERR, "timed out");
if (! daemonised)
goto eexit;
state = STATE_INIT;
SOCKET_MODE (SOCKET_CLOSED);
timeout = 0;
xid = 0;
free_dhcp (dhcp);
memset (dhcp, 0, sizeof (dhcp_t));
break;
case STATE_RELEASED:
dhcp->leasetime = -1;
break;
}
}
else if (retval > 0 && mode != SOCKET_CLOSED && FD_ISSET(iface->fd, &rset))
{
/* Allocate our buffer space for BPF.
We cannot do this until we have opened our socket as we don't
know how much of a buffer we need until then. */
if (! buffer)
buffer = xmalloc (iface->buffer_length);
buffer_len = iface->buffer_length;
buffer_pos = -1;
/* We loop through until our buffer is empty.
The benefit is that if we get >1 DHCP packet in our buffer and
the first one fails for any reason, we can use the next. */
memset (&message, 0, sizeof (struct dhcpmessage_t));
int valid = 0;
struct dhcp_t *new_dhcp;
new_dhcp = xmalloc (sizeof (dhcp_t));
while (buffer_pos != 0)
{
if (get_packet (iface, (unsigned char *) &message, buffer,
&buffer_len, &buffer_pos) < 0)
break;
if (xid != message.xid)
{
logger (LOG_ERR,
"ignoring packet with xid %d as it's not ours (%d)",
message.xid, xid);
continue;
}
logger (LOG_DEBUG, "got a packet with xid %d", message.xid);
memset (new_dhcp, 0, sizeof (dhcp_t));
if ((type = parse_dhcpmessage (new_dhcp, &message)) < 0)
{
logger (LOG_ERR, "failed to parse packet");
free_dhcp (new_dhcp);
continue;
}
/* If we got here then the DHCP packet is valid and appears to
be for us, so let's clear the buffer as we don't care about
any more DHCP packets at this point. */
valid = 1;
break;
}
/* No packets for us, so wait until we get one */
if (! valid)
{
free (new_dhcp);
continue;
}
/* new_dhcp is now our master DHCP message */
free_dhcp (dhcp);
free (dhcp);
dhcp = new_dhcp;
new_dhcp = NULL;
/* We should restart on a NAK */
if (type == DHCP_NAK)
{
logger (LOG_INFO, "received NAK: %s", dhcp->message);
state = STATE_INIT;
timeout = 0;
xid = 0;
free_dhcp (dhcp);
memset (dhcp, 0, sizeof (dhcp_t));
configure (options, iface, dhcp);
continue;
}
switch (state)
{
case STATE_INIT:
if (type == DHCP_OFFER)
{
logger (LOG_INFO, "offered lease of %s",
inet_ntoa (dhcp->address));
SEND_MESSAGE (DHCP_REQUEST);
state = STATE_REQUESTING;
}
break;
case STATE_RENEW_REQUESTED:
case STATE_REQUESTING:
case STATE_RENEWING:
case STATE_REBINDING:
if (type == DHCP_ACK)
{
SOCKET_MODE (SOCKET_CLOSED);
if (options->doarp && iface->previous_address.s_addr !=
dhcp->address.s_addr)
{
if (arp_check (iface, dhcp->address))
{
SOCKET_MODE (SOCKET_OPEN);
SEND_MESSAGE (DHCP_DECLINE);
SOCKET_MODE (SOCKET_CLOSED);
free_dhcp (dhcp);
memset (dhcp, 0, sizeof (dhcp));
if (daemonised)
configure (options, iface, dhcp);
xid = 0;
state = STATE_INIT;
/* RFC 2131 says that we should wait for 10 seconds
before doing anything else */
sleep (10);
continue;
}
}
if (! dhcp->leasetime)
{
dhcp->leasetime = DEFAULT_TIMEOUT;
logger(LOG_INFO,
"no lease time supplied, assuming %d seconds",
dhcp->leasetime);
}
if (! dhcp->renewaltime)
{
dhcp->renewaltime = dhcp->leasetime / 2;
logger (LOG_INFO,
"no renewal time supplied, assuming %d seconds",
dhcp->renewaltime);
}
if (! dhcp->rebindtime)
{
dhcp->rebindtime = (dhcp->leasetime * 0x7) >> 3;
logger (LOG_INFO,
"no rebind time supplied, assuming %d seconds",
dhcp->rebindtime);
}
if (dhcp->leasetime == -1)
logger (LOG_INFO, "leased %s for infinity",
inet_ntoa (dhcp->address));
else
logger (LOG_INFO, "leased %s for %u seconds",
inet_ntoa (dhcp->address),
dhcp->leasetime, dhcp->renewaltime);
state = STATE_BOUND;
timeout = dhcp->renewaltime;
xid = 0;
if (configure (options, iface, dhcp) < 0 && ! daemonised)
{
retval = -1;
goto eexit;
}
if (! daemonised)
{
if ((daemonise (options->pidfile)) < 0 )
{
retval = -1;
goto eexit;
}
daemonised = true;
}
}
else if (type == DHCP_OFFER)
logger (LOG_INFO, "got subsequent offer of %s, ignoring ",
inet_ntoa (dhcp->address));
else
logger (LOG_ERR,
"no idea what to do with DHCP type %d at this point",
type);
break;
}
}
else if (retval == -1 && errno == EINTR)
{
/* The interupt will be handled above */
}
else
{
/* An error occured. As we heavily depend on select, we abort. */
logger (LOG_ERR, "error on select: %s", strerror (errno));
retval = -1;
goto eexit;
}
}
eexit:
SOCKET_MODE (SOCKET_CLOSED);
/* Remove our config if we need to */
free_dhcp (dhcp);
memset (dhcp, 0, sizeof (dhcp_t));
if (iface->previous_address.s_addr != 0 && ! options->persistent && daemonised)
configure (options, iface, dhcp);
free (dhcp);
if (iface)
{
if (iface->previous_routes)
free_route (iface->previous_routes);
free (iface);
}
if (buffer)
free (buffer);
logger (LOG_INFO, "exiting");
/* Unlink our pidfile */
unlink (options->pidfile);
return retval;
}
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